1. Field of the Invention
The present invention relates to a device for supporting a saddle. More particularly, the present invention relates to a saddle supporting device which may be suitably used for supporting a saddle of the bicycle, a mountain bike, etc.
2. Description of the Prior Art
Hitherto, a saddle of a bicycle, a mountain bike, or the like was attached to a support frame (main frame) through a seat post serving as a rigid member, and shock absorption was effected mainly by the action of a metallic spring provided under the saddle, and the tires. However, the conventional saddle supporting structure, which employs the seat post as a rigid member, cannot provide a sufficient shock absorbing capacity for some types of bicycle, e.g., those which are required to provide soft cushioning, or those which are subjected to large impacts, such as mountain bikes. Accordingly, the prior art cannot provide a satisfactory ride quality and necessitates the support frame to be formed so as to have high strength in order to endure large impacts.
Under these circumstances, the present inventors have already developed and disclosed in Japanese Patent Application Number 3-232397 (1991) a saddle supporting device wherein a damper is slidably fitted in a guide tube secured to a support frame. An end portion of a piston rod of the damper is secured to the bottom of the guide tube, and a mounting member for a saddle is connected to a casing of the damper, which projects from the guide tube. With this supporting device, a shock that is applied to a wheel is transmitted to the saddle through the damper. Therefore, shocks are absorbed effectively over a wide range, so that the above-described problems can be overcome.
The above-described saddle supporting device, which includes the damper, suffers, however, from the following problems. In a case where the guide tube that slidably guides the damper is disposed with an inclination with respect to the vertical direction, external force is applied from the saddle to the damper in a direction different from the axial direction of the damper, which may cause sticking at the area of sliding contact between the damper (damper casing) and the guide tube, resulting in an unsmooth action of the damper. Further, in the above-described saddle supporting device, a means for preventing relative rotation between the guide tube and the damper is disposed in the guide tube. Therefore, the structure becomes complicated, inviting an increase in the cost.